Improvement in artificial legs



UNITED STATES PATENT OFFICE.

GEORGE L. SHEPARD, OF NEW YORK, N. Y.

IMPROVEMENT IN ARTIFICIALYLEGS.

Specification forming part of Letters Patent No. 42,799, dated May 17, 1864.

To all whom, it may concern:

Be it known that I, Gr. L. SHEPARD, ofthe city, county, and State of New York, have inventeda new and Improved Mode of Constructing Metallic Legs; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon.A

The nature of my invention consists in giving to the artificial limb or lower extremity a knee and ankle joint, as well as a joint or movement for the toes that combine all the necessary mechanical motions found to obtain in the natural limb.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

In Figure I, Ais a ball-and-socket joint, restricted to a simple hinge motion by the two lateral flanges, one of which is shown at a, and the extent of motion, limited by the abutments or shoulders b b at either end of the slot, in which the square portion c of the rod A B plays or vibrates from b to' b.

Dl D D is a C-shaped spring playing on a pivot attached at D to the rod A B, and in the same manner at its other end D to the side of the box E E, attached to or forming a part of the socket b e I, the object or action of which spring is to bring the rod A B, the analogue77 of the thigh bone, in line with the hollow rod E F, the analogue or substitute for the two bones, the tibia7 and bula, in the natural leg; or if the rod A B be fixed at rest, then to reverse that process, bringing E F in line with A- B.

,H is a coil-spring attached firmly to the sides of the box or case E E, with its free end taking hold of or resting upon the free end of the spring Dll D D, which is turned backward for that purpose. The object ofthe coilspring is to increase the power of the C- spring, and at the same time act with most efciency in initiating the movement for extension when the limb is flexed or bent, and also further assists the action of the C-spring in steadying the knee-joint when A B and F F are in the same perpendicular line and bearing the weight of the body.

I I I I are metallic diaphragms attached to the metallic shell o o, (in form resembling the natural leg,) and to which the box or case E E and the stationary parts of A B and E E are attached, thus giving iixed and permanent unity to all the component parts of the lower extremity, between the thigh and the ankle- `joint-to wit, the socket b e b, the spring box or case E E, the rod F F, attached to it by the screw K, the ball L ot' the ankle-joint,

'the two diaphragms I I', and, lastly, the

outer shell o o; for it will be observed that this shell terminates at the ankle-joint, and forms with the shell of the foot a species of sleeve or slipjoint,7 and that the socket M M is in Astable or xcd connection with the foot by means of the Aplate N N and its connection with the shell of the foot, as well as by the standards or supports I) I), rising from and firmly attached to the lower portion or floorof the heel.

The manner in which the necessary motions of the foot is obtainedi. e., its iexion and extension, its slightly lateral, as well as horizontal, motion, and also the manner in which all those movements are arrested, and the foot restored to a right-angled position to the leg or shaft F E, as when standing and bearing the weight ofthe body-will be apparent upon examining in detail the mechanical construction or means by which those ends or objects are accomplished.

rlhe Yball or sphere L plays upon the pivot Q., passing through the ball laterally, from side to side',1and. iixed or held in its position by being riveted in the shell or socket, which latter is constructed in halves and held together by rivets or screws in the lugs M M after the ball is introduced.

The holein the ball through which the pivot asses is not of the same dimensions throughout its length, but, as shown in Fig. III, is of conical or F spheroidal7 shape, ot' the size of the pin in the center and enlarging in a curvilinear manner toward either side, thus combining or giving toythe ball and its at@ tachments, besides the hinge motion, a slightly lateral or rocking movement. Both of these motions, -it will be observed, are checkedand limited by the iianges R R above, and by the edges of the socket S S' below.

The construction of the upper opening, R R, of the socket M M is also of a conical shape-4'. e., oblong above and its sides terminatin g in a circle where ittouches the ball, as shown in Fig. 1I, which figure also shows the square form of the shoulder of the rod or arm V K, where it rises from the ball L, Fig. I. The oblong i'orm ot' this opening being longer fore and aft -t'. e., in line with the foot, and narrower from side to sidegives to the iiexion and extension movemt nts of the foot the greater range ofmotion, and in like manner limits the lateral or, so to speak, ankle-turning77 movements when the heel is not placed squarely on the ground, this construction and arrangement of the mechanism constituting the articial ormechanical ankle-joint-z".V e., the socket or case, the ball, and the pivot passing through its center, while it gives to the foot all the required movement at the same time restricts those movements within the necessary bounds or limits. But to modulate and still further restrain those motions, and to render them as they aie in the natural joint measurably gradual-z'. e., not sudden or abrupt, and also t i restore the foot to a state of rest from ilexion and extension, and to aid in retaining it inthat position, as in the standing posture when the footis at right angles with the legl have recourse to the twoJews-harp7 springs s s s, Figs. I and IV. These springs are firmly riveted at their base to the interior or floor ot' the heel by the standard S D, and then elastic extremities coming together and meeting above form, as it were, a yielding socket for the reception of the square end of the rod T. Besides acting as a rivet for holding or attaching these springs to the heel, this standard, it will be seen, by taking with i the end of the rod L T the pressure or bearing of the ends of the springs, allows only those to act which are displaced or pressed upon by the movements of the rod F L T out of its perpendicular or ri gh t-lined direction with it.

The two pins 2 2 2 2, Fig. IV, passing` through the elongated ends ofone spring, acts as a means of steadying those ends, and their distance apart limits the motion of the ends ofthe lateral spring, playing between them and the elongated ends of the other spring. The evident eftect of the constant pressure of these springs acting on the extremity of the rod T will be to restore the whole rod F F V T to a perpendicular position when the foot is stationary and the lower portion of the leg is bent or inclined in any direction, or, which is virtually the same thing, will restore the foot to a right-angled position to the lower leg when that position of rest is disturbed in the et't'ort otlocomotion,'and as the principal motion in such case is that of flexion and eXtension ot' the foot this motion is accomplished by the pin Q Q passing laterally through the ball L, thus modifying and converting the ordinary ball-and-socket motion or joint into ahinge or Vibratorymovement, while, as before observed,

t'ie ununit'orm bore or size of the hole in the ball,

The only remaining movement or construction to be specied or described is that of the foot at the great-toe77 joint, as shown at W in Figs. I and IV. This joint, like that of the knee and anklejoints, is a species of sleeve f' or slip joint. The shell forming the anterior portion of the foot is made with a shoulder and fits or plays within the shell of the foot at that place, and might be distinguished or designated as a looped slip-joint77 from the lnanner in which the toes and fore part ofthe f'oot is made to retain its movable position. This object is accomplished by an india-rubber band or loop, V V, passing round the two pins or small rods Y Y, extending across the i'oot, having their extremities riveted or fastened into the shell oi' the foot. The eiiect of this method of constructing the jointis to give it a modiiied hinge-joint movement, and the location ot' the pins and loop a little more than or about half-way between the top and bottom of the foot, divides the vibration or motion, and is thus a much more close imitation of t-he natural joint than if this portion of the foot was made to hinge on either the top or the bottom of that part of the shell.

For the well-known advantage in avoiding the wear from friction I construct the ball and socket out ot' metals of dit't'erent degrees of hardness.

`What I claim as my invention,and desire to secure by Letters Patent, is

1. Converting the ball-and-socket joint for l the knee into a limited hingejoint by means ofthe slot t a, and the ila-nges b b, regulating and limiting the motion.

2. The application of the bow or C-spring D D with its bent or bell-crank lever, in connection or in combination with the coil or watch spring, as before specified and described.

3. In the ankle-joint, converting the otherwise more free movements ofthe ball-andsocket joint into a modified hinge-joint by the application or by means of, iirst, the oblongslot, or opening above and below, with the flanges as described; second, by the pin or pivot passing through the center of the ball horizontally from side to side; third, by the shape and form of the hole through the center of the ball, as more particularly described in the specification and drawings herewith connected. All of which means, as combined, I claim as my invention.

4. For the purposes hereinbefore specified and set forth, the application of the two Jewsharp springs and standard underneath the socket, together with that of the two pins their ends riveted to the inner and outer side passing through the ends of the springs, as of the foot, as heretofore set forth and dedescribed and set forth in the specification scribed.

and drawings. GEO. L. SHEPARD.

5. The mode or method of constructing the Witnesses:

toejoint by the application of the indiar-rub- D. B. BURNETT,

ber band passing round the two pins or rods, J. M. GRENELL. 

